sounds for electric vehicles
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Sounds for Electric Vehicles. QRTV-06-09. Defining Sounder Criteria Presented by Henry Morgan Edited from paper prepared and presented by Prof. Geoff Leventhall to ISO Apr 2011 Acoustical Consultant [email protected]. What Should a Sounder for Quite Cars Achieve?. - PowerPoint PPT PresentationTRANSCRIPT
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Defining Sounder Criteria
Presented by Henry Morgan
Edited from paper prepared and presented by Prof. Geoff Leventhall to ISO Apr 2011
Acoustical Consultant
Sounds for Electric Vehicles
QRTV-06-09
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What Should a Sounder for Quite
Cars Achieve? Safety:
Audibility, Locatability, Directivity
Environmental: Acceptability, Directivity, Attenuation
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AudibilityDepends on loudness (phons) or sound pressure level (dBA) compared with background noise
Why phons? Tests show that, for equal dBA, broadband sounds are louder than tonal sounds.
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ALARM SOUND
LAeq dBA
Loudness Phon
Broad band
92.3 103.2
Complex
1450Hz
92.1 98.5
Loudness of broadband and tonal back alarms
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Depends on ratio source diameter to wavelength For 0.1m source,
D/lambda = 0.25 at 850HzD/lambda = 1 at 3400Hz
Directional radiation from a piston source
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A-Weighted Directivity
Prius Hybrid fitted with Brigade broad band prototype sounder
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Limit the directionality
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Broadband Sound
• Broadband sound contains complete auditory information for location
• Greater higher frequency content gives:
greater directivity
greater attenuation
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Equal loudness contours
range of added sound
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White soundWhite
-50
-45
-40
-35
-30
-25
-20
-15
-10
0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000
Frequency Hz
Rel
ativ
e le
vel d
B
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Pink SoundPink
-50
-45
-40
-35
-30
-25
-20
-15
-10
0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000
Frequency Hz
Rela
tive
leve
l dB
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Band Limited SoundBand limited
-80
-70
-60
-50
-40
-30
-20
-10
0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000
Frequency Hz
Rel
ativ
e le
vel d
B
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500Hz to 3500Hz
500Hz to 3500Hz
-30
-25
-20
-15
-10
-5
0
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Frequency Hz
Re
lati
ve
lev
el d
B
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A back alarm soundBB reversing alarm
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000
Frequency Hz
Rel
ativ
e le
vel d
B
15
Multiple tone soundTones
-80
-70
-60
-50
-40
-30
-20
-10
0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000
Frequency Hz
Rel
ativ
e le
vel
dB
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Pink Broadband sound for EVs
Car sound
-50
-45
-40
-35
-30
-25
-20
-15
-10
0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000
Frequency Hz
Rela
tive level d
B
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All the sounds
White
Pink
Band limited 1
band limited 2
Back alarm
Multiple tone
Pink BB for EVs